THE LINEMAN
// BY DYLAN DOYLE — NETWORK ANALYST
CCNA 200-301 · PACKET TRACER LABS
INTERACTIVE STUDY TOOLS · FORTINET HOME LAB
STUDYING IN PUBLIC.
ONE PACKET AT A TIME._
INTERACTIVE STUDY TOOLS · FORTINET HOME LAB
STUDYING IN PUBLIC.
ONE PACKET AT A TIME._
★ CHOOSE YOUR PATH
Five tracks. Pick the one closest to what you're trying to build right now. Each track is a curated order through the labs, articles, and tools — not a content dump.
★ LATEST POSTS
GUIDE
[ FEATURED · CCNA ]
WHY SUBNETTING FINALLY
CLICKED FOR ME Three weeks of confusion. One diagram that changed everything. Here's the mental model that actually works — and why most guides start from the wrong end.
CLICKED FOR ME Three weeks of confusion. One diagram that changed everything. Here's the mental model that actually works — and why most guides start from the wrong end.
> 192.168.1.0/24
> VLSM CALC...
> /25 = 128 hosts
> /26 = 64 hosts
> /27 = 32 hosts
> DONE_
GUIDE
[ CCNA · OSPF · LSA TYPES ]
OSPF MULTI-AREA & LSA TYPES:> VLSM CALC...
> /25 = 128 hosts
> /26 = 64 hosts
> /27 = 32 hosts
> DONE_
WHAT EACH LSA CARRIES Why OSPF carves the domain into areas, the four router roles (internal / backbone / ABR / ASBR), every CCNA-relevant LSA type (1, 2, 3, 4, 5, 7) with originator and flooding scope, and the five OSPF packet types tied to the adjacency state machine. GUIDE [ CCNA · IPV6 ] IPV6 FOR THE CCNA:
COMPRESSION, TYPES & EUI-64 The short IPv6 guide for the exam — 128-bit anatomy, the two compression rules, the six address types, and EUI-64 step-by-step. Paired with three free drill tools. GUIDE [ CCNA · ROUTING · OSPF ] OSPF EXPLAINED:
LINK-STATE ROUTING FOR THE CCNA No CLI — just the mental model. Distance-vector vs link-state, LSDB & SPF, areas, router-ID picking order, the process-ID trap, and wildcard masks. Read this before you touch the lab. GUIDE [ CCNA · OSPF · TROUBLESHOOTING ] OSPF ADJACENCY STATES:
WHY YOURS IS STUCK IN EXSTART Every OSPF state — DOWN, INIT, 2-WAY, EXSTART, EXCHANGE, FULL — and the one-line fix for each failure mode. MTU mismatch, one-way Hellos, flapping timers, and the troubleshooting decision tree. GUIDE [ NETWORKING · VPN · TROUBLESHOOTING ] THE 1500-BYTE LIE:
WHY YOUR VPN HANGS ON BIG FILES The VPN's up. Pings are 18ms. Web works. Then a 50MB download hangs at 4%. Here's the math, the captures, and the MSS-clamping fix — per platform. REFERENCE [ CCNA · REFERENCE ] SUBNETTING CHEAT SHEET:
CIDR, BLOCK SIZES & HOST COUNTS Every prefix /8 through /32 in one place. Subnet mask, block size, total addresses, usable hosts, and wildcard mask. Save the image or bookmark the page.
⬇ PRACTICE LABS
[ FREE · PACKET TRACER ]
VLAN SEGMENTATION
LAB 1 · TRAINEE
Two switches, six PCs. Students on VLAN 10, Staff on VLAN 100. Configure from scratch and verify isolation.
▶ READ + DOWNLOAD
[ FREE · PACKET TRACER ]
INTER-VLAN ROUTING
LAB 2 · ANALYST
Add SW3 and a router. Configure dot1q subinterfaces on R1 to route between Student and Staff subnets.
▶ READ + DOWNLOAD
[ FREE · BROWSER LAB ]
STP ROOT BRIDGE ELECTION
LAB 3 · ANALYST
The 4-step STP algorithm, port roles, port costs — then drill it in an interactive browser lab with quiz mode and a sandbox.
▶ READ + LAUNCH LAB
[ FREE · PACKET TRACER ]
RAPID SPANNING TREE
LAB 4 · ANALYST
Same triangle as Lab 3, faster recovery. Configure 802.1w / Rapid-PVST+ and watch a link failure reconverge in under a second.
▶ READ + DOWNLOAD
[ FREE · PACKET TRACER ]
OSPF SINGLE AREA
LAB 5 · ANALYST
Multilayer switch and one router, three PC LANs and a server segment. Configure OSPFv2 area 0, watch the adjacency reach FULL, and verify routes end-to-end.
▶ READ + DOWNLOAD
[ FREE · PACKET TRACER ]
STATIC & FLOATING STATIC
LAB 6 · ANALYST
Six routers, four LANs. Build full reachability with nothing but
ip route, then watch AD-100 statics beat pre-configured OSPF on a contested link. Bonus: flip the contest with a floating static.
▶ READ + DOWNLOAD
★ ABOUT
░░░░░░░
░ DD ░
░░░░░░░
DYLAN DOYLE
NET ANALYST · LVL 23
░ DD ░
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ROUTING
72
FORTINET
80
LINUX
65
ENDURANCE
85
CCNA
45
I used to hold the line on a football field. Now I hold it in a network rack.
I'm Dylan Doyle — a network analyst at Halton District School Board, based in Burlington, ON. I studied the BIT NET joint program between Carleton University and Algonquin College — four years learning how networks actually work, then two summers at Halton's IS-IS department proving it. They kept me on full time after graduation.
Now I'm working toward my CCNA, running a Fortinet home lab — FortiGate 60F, FortiSwitch 124D, and a FortiAP 421E — and self-hosting everything I build on Linux from scratch. This site included.
Outside the rack, I'm training. I've completed an Olympic triathlon and a half marathon, and I'm building toward a full Ironman — slowly, deliberately, the same way I approach everything. One packet at a time.
TheLineman is where I document all of it — the certs, the lab, the grind. If you're on a similar path, pull up a chair._
CCNA
FORTINET
LINUX
APACHE2
CARLETON BIT NET
HALTON DSB
IRONMAN
BURLINGTON ON
★ CONTACT
★ RESOURCES
JEREMY'S IT LAB
Best free CCNA course on YouTube. Start here.
BOSON EXSIM
Best CCNA practice exams. Worth every penny.
GNS3
Free network sim. Run real IOS images locally.
SUBNETTING
Drill subnetting until it's automatic. Daily.
FORTINET DOCS
Official Fortinet documentation. Always open.
MY GITHUB
Lab configs, scripts, and projects. All open.
⚙ HOME LAB
[ FIREWALL ]
FORTIGATE
60F
Perimeter firewall, VPN, threat inspection. The brain of the home lab. Full UTM enabled.
● ONLINE
[ SWITCH ]
FORTISWITCH
124D
24-port managed switch. VLANs, trunking, FortiLink managed directly by the FortiGate.
● ONLINE
[ WIRELESS ]
FORTIAP
421E
Dual-band AP managed via FortiGate wireless controller. Multiple SSIDs per VLAN.
● ONLINE
[ SERVER ]
LINUX BOX
POP!_OS · APACHE2
Self-hosted web server running Apache2. Hosts this site. Built and configured from scratch.
● ONLINE
[ MONITOR ]
OBSERVABILITY
PLANNED: GRAFANA
Deploying Grafana + Prometheus for full visibility across the Fortinet stack and Linux server.
◌ IN PROGRESS
[ CERT LAB ]
CCNA STUDY ENV
GNS3 + PACKET TRACER
Virtual topologies for exam scenarios. OSPF, BGP, STP, and VLANs running daily.
◌ ACTIVE
★ CURRENTLY BUILDING
2026-05-22
Build log live · Completion tracking sitewide · No-dead-ends module on top OSPF pages
2026-05-22
Platform redesign blueprint — 10-pillar retention audit drafted
2026-05-21
Lab 9 — CDP & LLDP Neighbor Discovery shipped · Domain 2 now 56% covered
2026-05-21
Sitewide affiliate buildout · sticky OCG banner · 51 amazon.ca links got rel="sponsored"
2026-05-19
Lab 8 OSPF Multi-Area + Article 12 LSA Types — launched together